Field of the Invention
The present invention relates to a belt-driven continuously variable transmission having a pair of pulleys and a belt running between the pulleys, and more particularly, to a lubrication device for lubricating a contact point between the pulley and the belt.
Discussion of the Related Art
JP-A-2014-5873 describes a lubrication device for continuously variable transmissions adapted to apply lubricant to an inner circumferential region of a conical face. According to the teachings of JP-A-2014-5873, the lubrication device is provided with a stabilizer adapted to suppress vibrations of the belt by a pair of plate members. The stabilizer is allowed to tilt around a support shaft in accordance with a speed ratio. The support shaft has a first outlet opening toward a conical face of one of the pulleys, a second outlet opening toward a conical face of the other pulley, and a hollow portion providing a connection between those outlets. In the continuously variable transmission taught by JP-A-2014-5873, a running diameter of the belt in one of the pulleys is reduced by expanding a running diameter of the belt in the other pulley. Consequently, the stabilizer is tilted so that the one of outlets opening toward the pulley in which the running diameter of the belt is expanded is closed to deliver larger amount of the oil to the other pulley in which the running diameter of the belt is reduced.
JP-A-2014-13068 also describes a lubrication device for continuously transmissions. According to the teachings of JP-A-2014-13068, the lubrication device is adapted to deliver oil to a primary shaft and a secondary shaft from a feeding conduit extends between a primary pulley and a secondary pulley. The lubrication device taught by JP-A-2014-13068 is provided with a guide member for guiding the oil discharged from the feeding conduit toward a belt groove of the pulley.
Thus, the lubrication devices taught by JP-A-2014-5873 and JP-A-2014-13068 are adapted to deliver the oil to the conical face of the pulley in which a running radius of the belt is reduced. However, in the belt-driven continuously variable transmission, running diameters of the belt are varied continuously in accordance with a speed ratio. That is, according to the teachings of the above-mentioned prior art documents, the oil may not be applied directly to a contact point between the belt and the pulley depending on the speed ratio. Consequently, the pulley or belt may be damaged due to lack of lubricant. In addition, the oil delivered to the conical face of the pulley may be scattered centrifugally and hence oil consumption would be increased.
The present invention has been conceived noting the foregoing technical problems, and it is therefore an object of the present invention is to provide a lubrication device for a belt-driven continuously variable transmission that can apply oil sufficiently to a contact point between a pulley and a belt irrespective of speed ratio.